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Your Weight and IVF Success Rates


How Does Your Weight Affect IVF?

The health benefits of maintaining a normal weight have long been understood in the medical community. People who are overweight have a higher incidence of diabetes, heart disease, high blood pressure and cancer, and have a greater risk of complications during pregnancy. People who are underweight or overweight, both men and women, suffer from a higher chance of infertility. Often this is due to hormonal problems caused by too much or too little body fat.

IVF treatment can improve your chances of conceiving if you have fertility problems. However, did you know that how much you weigh can affect your success rates with IVF? Recent studies have shed some light on the effects of weight on fertility and on IVF success.

What is BMI?

BMI is body mass index, a measure of body fat based on height and weight that applies to adult men and women. A BMI of less than 18.5 is considered underweight, while the normal range is 18.5 – 24.9. Overweight is 25 – 29.9, and 30 or greater is considered obese. There are many BMI calculators online; here is a link to one from the National Institutes of Health. Many people are surprised to find out they are actually overweight or even obese!

Obesity, Egg Quality, and Live Birth Rates in IVF

Research has shown that obesity may affect egg quality and may make it harder for overweight women to have successful IVF with their own eggs. A recent study indicated that obese women may need different doses of fertility drugs than normal-weight women in order to ensure that their eggs ripen at the right time and can be extracted for IVF.

“Our findings indicate obese women may need a different or increased dosing regimen to improve fertility treatment outcomes,” Dr. Nanette Santoro of the University of Colorado at Denver, an author of the study, said in a press release.

Another large study published in 2013 reviewed over 9,500 egg donation IVF treatments in Spain. The egg donors were all of normal weight, and the recipients were divided into four groups: underweight, normal, overweight and obese. The rates of embryo implantation, pregnancy and live birth all declined significantly as body mass index (BMI), increased.

Obese women who received eggs from normal weight donors had a 23 percent lower implantation rate than normal weight recipients, a 19 percent lower clinical pregnancy rate, and a 27 percent lower live birth rate. For comparison, results showed that the live birth rates were 38.6 percent in the underweight group, 37.9 percent in the normal weight group, 34.9 percent in the overweight group, and 27.7 percent in the obese group.

What Can You Do?

Many studies have demonstrated that fertility decreases as weight increases above normal. On the flip side, overweight patients who lose a significant amount of weight may be able to ovulate normally and not require fertility drugs—or fertility treatment. But if you are overweight or obese, loss of as little as 10 percent of your total body weight can be enough to make a difference in the success of your fertility treatment.

Losing weight has never been an easy proposition. But it can make a huge difference in your efforts to start a family. Talk to your doctor about diet and exercise, and see if you can make a plan you can stick with for the long haul.